The present invention relates generally to resin-based sealing materials for use in closing gaps and holes in a variety of structural environments.
In the automotive industry it is often necessary to seal gaps and joints in metal structures using an adhesive bead, plug or patch. For example, where a stamping and a structural beam meet a longitudinal gap may arise. In addition, drainage holes, assembly access holes, fastening holes and the like are often formed in automobile body structures and must be subsequently closed. As will be appreciated by those skilled in the art, if left unsealed these gaps and holes allow dust and fumes to enter the passenger compartment and create a source for water leakage and corrosion.
It is known that the cost of resins often exceeds that of other materials. Accordingly, significant research has been conducted to produce resin-based sealants which take advantage of low-cost starting materials.
It is also known that when manufacturing plants spray automotive bodies in paint spray booths, only 50-60% of the paint spray actually adheres to the surface being painted. Typically, that portion of the paint spray that does not adhere (the xe2x80x9coversprayxe2x80x9d) is exhausted from the spray booth by means of a wet scrubber system. Of course, a wide variety of paint formulations are used in the industry. The resulting overspray, which may be a mixture of different paint formulations from multiple paint applications, is generally treated in solution to detackify the paint particles so they are non-sticky. Next, a process the paint particles are flocculated so they can be collected. Heat is then applied to the resulting paint solids to drive off all of the volatiles and water. Once the paint solids are dried and sized, they have the consistency of a powder; the chemistry of these solids is very similar to the paint that was applied in the paint booth.
In one aspect the present invention provides resin-based materials for use as sealants. The inventive sealant materials include as a key component processed overspray from an automotive paint booth. The processed paint booth overspray preferably comprises substantially fully-cured overspray resins in particulate form. In one aspect the paint booth overspray is principally a substantially fully-cured acrylic material. In another aspect, the paint booth overspray also includes substantially fully-cured epoxy material. As used herein, xe2x80x9csubstantially fully-curedxe2x80x9d shall mean the resins are substantially inert; that is, the polymers do not undergo any significant further polymerization or cross linking. In one aspect, the inventive compositions also include a blowing agent to produce an expandable material.
In another aspect the present invention provides a method of sealing a gap with a resin-based sealant materials which include as a component processed overspray from an automotive paint booth.
In still another aspect of the present invention, a method of making a sealant material which contains processed overspray from an automotive paint booth.